Natural gas can be extremely dangerous if uncontained. However, should it escape into the atmosphere its presence frequently will be unknown since natural gas is odorless. Therefore, odorants are injected into the gas to make it odoriferous. Usually this occurs immediately before the gas is transported from one location to another; by pumping the odorant into a natural gas pipeline.
Various devices are presently available to inject odorants or other fluids into a pipeline. Most of these devices inject a volume of odorant into the pipeline independent of the flow rate therein. Since flow rates are not always constant, these devices waste odorant by injecting an excess amount of it into the pipeline.
Others have overcome this inefficiency by monitoring the fluid flow rate in the pipeline and adjusting the amount of fluid injected therein accordingly. These devices are similar in the sense that they are all electronically controlled. Typically, they will have a means for converting the flow rate into a continuous pneumatic signal which is then converted by a flow transducer into a continuous electronic signal. Using a linear integrator transmitter, the continuous electronic signal is converted into a pulsating electronic signal. The pulsating signal controls a solenoid valve which produces a pulsating pneumatic signal. Each pneumatic pulsation is sent to a reciprocating pump which actuates in response to inject a given amount of chemical into the pipeline. However, the use of these devices has not proven entirely satisfactory. They are expensive both because they require costly electronic instrumentation; and because they must be partially or totally encased to reduce the likelihood of a natural gas explosion, a major concern at well sites. Additionally, their use requires a well site source of electricity to be secured and maintained at all times, problematic when the well site is at an offshore or remote inland location.